A challenging use of flow variables

Demo.knwf (58.2 KB)

Dear all,

Please help me out of this stalemate!
I have been trying (and failing) for more than 3 days now to figure out a way to automate my one case workflow to deal with 20 000 different cases.
I need to calculate a simple difference but what is difficult here and out of my experience so far is the use of flow variables to select what to substract from what.
Please see above the attached photo with what i want to obtain and the snapshot and workflow with what i have managed to build so far.
I will be very grateful for whatever help/ ideas anyone can provide!

1 Like

Hi @ElenaM & welcome to the KNIME community !

Please find below a possible solution if I understood well the problem you need to solve:

Demo with a possible solution.knwf (92.9 KB)

Anyway, I believe the spirit of the solution is here but please do not hesitate to come back and ask for help. And definitely do not wait 3 days for a solution. We are happy here to help :wink: !



Edit: I just noticed that your dates are not sorted. Maybe you would need to sort the rows first by date before applying my solution. Just in case :wink:


Hello aworker,

Thank you for your effort in helping me out!
Unfortunately the result is not what I was looking for but in the meantime I found the solution.
Thank you once again for taking the time!

Hello @ElenaM

Thanks for the feedback. In this case, could you please post here your solution? I believe everybody would be happy to know what you were looking for as solution. You could then check your own answer as the valid solution so that other people can find it easily and benefit from it. Knowledge should flow in both senses for the benefit of the whole the community :innocent:

Thanks & regards,


Sure and I am happy to share.
My target was to find the price difference for the same scale quantity (say scale quantity 100 or 7000) while said quantity belong to various “condition record no.” but just one “Key”
In my first approach I was pivoting the data and doing the calculations and I thought I need flow variables to have the workflow go through all the “Key” cases and all the “Condition record no.” existing for each “key”. But actually it was all a matter of sorting the data differently and then a Lag column would work the way I needed it.
Also I think in my first post i did not use words to describe well what I need, thinking that by attaching a image of the data and by
Demo_solution.knwf (17.2 KB)
analyzing my workflow steps it will be clear. I am not sure that approach was a good one so I will try to be more explicit in the future.


Thanks for sharing @ElenaM. I had a look at your solution and now I understood what you needed to implement.

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